Bölts is one of the most successful German cyclists, and from the beginning of his career he distinguished himself as a coureageous rider who liked to get into breakaways. Bölts began his professional career in 1989 with Team Stuttgart, from which Team Telekom were formed in 1991.
From 1992 to 2003, Bölts took part in twelve consecutive Tours de France, arriving in Paris on every occasion, both of which feats are German records. His best placing in the hardest stage race in the world was in 1994, when he was ninth. In 1996 and 1997, he was an important helper of teammates and eventual winners of the Tour, Bjarne Riis and Jan Ullrich. During the 1997 Tour, he was noted for the words he shouted to Ullrich when the latter was about to crack: Quäl dich, du Sau! (force yourself, you sod!).
Some of his greatest victories include three German road national titles (1990-1995-1999), the Clásica de San Sebastián in 1996 or a stage win at the 1992 Giro d'Italia. He also is the only German rider to have won the Dauphiné Libéré, which he did in 1997, a year in which he was also fourth in the World Cycling Championships.
For his last season as a professional, Bölts moved to Team Gerolsteiner. After he retired in 2004, he became one of the team's directeurs sportif, and is responsible for race preparations, strategies and contacts with other teams and cyclists.
In the wake of the 2007 Team T-Mobile scandal Bölts confessed publicly on May 23 having used EPO and growth hormones in preparation for the Tour the France 1996, continuing with the practise in 1997. In consequence of this Bölts resigned as the sports director of Team Gerolsteiner on May 24 2007